Lubricant composition



2,7 58,086 Patented Aug. 7, 1956 Fit:

LUBRICANT COMPOSITION Frank A. Stuart, Richmond, and Warren Lowe, Berkeley, Calrfi, assignors to California Research Corporation, San Francisco, Calif., a corporation of Delaware No Drawing. Application June 28, 1952, Serial No. 296,248

9 Claims. (Cl. 25232.5)

This invention relates to a lubricant composition, and is particularly directed to the provision of a composition of their character which incorporates a branched chain amino compound.

It is known that amines and amine salts have the ability to impart good detergency characteristics to lubricating oils, whereby the various insoluble products formed as a result of oxidative attack on the fuel or from combustion of the fuel are maintained in suspension in the oil. However, while the amino compounds which have heretofore been employed in lubricating oils possess satisfactory detergency qualities, their field of application as lubricant additives has been greatly curtailed due to their unfavorable action from a corrosion standpoint under the more rigorous conditions of service. Thus, while oils containing amino additives are satisfactory and do not appear to have any adverse effects when employed under mild service conditions, such oils are not adapted for use in Diesel and other internal combustion engines which are operated at relatively elevated temperatures. Corrosion difliculties with amine-compounded oils soon become severe in such service, particularly in the presence of metals which are susceptible to attack by acidic and/or peroxidic decomposition products of the oil or other materials. Bearing metals such as copper-lead, cadmium-silver, cadmium-nickel, so-called high lead bearing alloys, and the like, are particularly prone to attack by these decomposition products, and it appears that under the more rigorous operating conditions mentioned above, the amino compounds actually promote corrosion of the bearing metal surfaces by the oil.

As is pointed out in copending application, Serial No.

237,684, filed July 19, 1951, many of the oil additives which normally act to suppress or inhibit this corrosive attack on bearing metal surfaces are not appreciably effective for this purpose when employed in oils containing amino additives, particularly when said oils are employed-in Diesel and other internal combustion engines where relatively high temperature conditions are encountered. It is disclosed in said copending application that oxidation attack on hard bearing metals at elevated temperatures by amino compound-containing oils can be reduced to the desired minimum by the addition to the oil of a benzothiazyl dialiphatic dithiocarbamate. However, while use of the latter inhibitors is satisfactory from a performance standpoint, they are relatively expensive chemicals, and the introduction thereof into the oil materially adds to the cost of the product.

Accordingly, it would be desirable if a class of amino compounds were available which would impart good detergency characteristics to lubricating oils without appreciably increasing the corrosivity of the resulting com position to bearing metal surfaces even under rigorous service conditions, and it forms the principal object of this invention to provide such a class of amino compounds. It is our discovery that by incorporating in an oil of lubricating viscosity a minor percentage of one or v more amines or amine salts of the type having at least one 2. branched aliphatic chain of 10 or more carbon atoms attached to the amino nitrogen atom, there is obtained a composition having excellent detergency characteristics and low corrosivity to bearing metal and other surfaces coming into contact with the oil under all service conditions. These beneficial results are obtained without the necessary use in the oil of dithiocarbamate or other co'rrosion-inhibitory additives. Further, it has been found that the branched chain amino compounds disclosed herein are superior to other amino compounds inthat they are more resistant to oxidative attack and have a lower pour point.

More specifically, the amino compounds which are useful in a practice of the present invention are those of the type having the general formula In the formula R1 is a branched chain radical of aliphatic character containing at least 10 carbon atoms, which terminology is employed herein to designate both unsubstituted aliphatic radicals, as well as those which are substituted to a minor extent by one or more substituent groups such as phenyl, benzyl, cyclohexyl, chloro, amino, hydroxy, or the like. R2 and R3 in said formula are selected from the group consisting of hydrogen atoms and organic radicals which are essentially hydrocarbonaceous in character. By essentially hydrocarbonaceous radicals are meant those which are composed mainly of hydrogen and carbon, but which can also contain minor amounts of non-hydrocarbon substituents such as chloro, bromo, hydroxyl and amino groups.

In the preferred practice of this invention R1 represents a branched chain alkyl group of 10 or more carbon atoms which, more preferably, is attached to the amino nitrogen atom through a tertiary carbon atom, While R2 and h are preferably hydrogen atoms or hydrocarbon radicals.

The following primary, secondary and tertiary amines are illustrative of those which can be employed in carrying out the present invention:

PRIMARY AMINES Isooctadecyl amine 1 1,1-dimethyldodecylamine 1,1-dimethyloctadecylamine l-methyl-l-benzyl-tridecylamine l-methyl-l-isopropyloctylamine 1,l-diethyl-4-methyldodecylamine 1, 1,4,6,6-pentamethylheptylamine v 1,1,3,3 ,5 ,S-hexamethylhexylamiue N-n-octadecyl-isootadecyl amine N-phenyl-2-isopropyldodecylamine N-cyclohexyl-1-methyl-3-ethylheptadecylamine N-methyl-N-phenyl- 1 l-dimethyldodecylamine and Haas Company under tlle tradenmne radical in this compound being derived on I the polymerization of isobutylene.

' to a. tertiary carbon atom, is mainly CwI'ImNHh I from 275 to 340 C.

amines" mentioned herein are obtained by replacement. of one I or both of the 'hydrogen'atoms onthc am ne nil acids. either'beused as such or as the partial esters with various 3 N-benzyl-lethyldccylaminc N-methallyl-l-sec. butyloctylaminc iN-mcthyl-2 ethyl-4 decenylamine TERTIARY AMINES N,N-'dimcthyl-l-sec. butyl-4-ethyloctylamine- I N-ethyl'N-butyl-l-mcthyl-4-cthyloctylamine The product isooctadecylamine is marketed by Bob the *isooctadecyl The formula of this product, wherein the amino nitrogen atom is attached directly It has a; specific gravity. (25 C.) of 0.828, a 1 I (25 C.) of 1.455, and a boiling point range (5, to95%) of at 760 mun/Hg. Other isooctsdecylthe indicated radical (s) I The amine salts whose use comes within the scope of I estcrification of the. hydroxy groups in alkylcnc oxide polymer such as, for example, the acetate of the Z-cthyl Another 7 hexanol-initi'ated polymer of propylene oxide. 7 important class of synthetic oils comprises the high mo- I lecular weight esters, as, for example, di(ethylhexyl) sebacate.

The compounded oils of this invention find utility. not only as crankcase lubricants for internal combustion engines (including spark-ignition and diesel engines), but I also as turbine oils, cable oils, electric switchoils, transformer oils'and hydraulic oils and, the like. Further,

the branched chain amino compounding. agents of this invention can be added to the base oil in conjunction with etc.), pour point depressants, oiliness agents, extreme l'figfll'llliollllll' v I pressure addition agcnts,-ant1-ox1dants, corrosion-inhibltas. sulfonic or phospho'nic acids- Representative acids I which' can be employed in forming the branched chain amine salts'arc formic, acetic, propionic, butyric, .caproic,

lauric, stearic, arachidic, 'oleic,v benzoic, toluic, naph thenic, cetylphosphoric, cyclohexanephosphonic, cetylsul- I furic, petroleumsulfonic, maleic, tartic, benzoic, phthalic,

citric, chlorostearic', phenylstcaric and mcrcaptostearic In :forming the salts, the .polybasic acids can alcohols such as ethanol, hexanol, hcxadecanol and the like. Representative branched chain amine salts are ;isooc tadccyl amine benz'oate, di( 1-methy1-4 ethyl:do

dccylarnine) adipate, l-isopropyldecylamino oleate, N,'N-

dimethyl-l-scc. butyloctylarnine naphthenate, l-(3'-ethylpcntyl) 4 ethyloctylamine acetate, N-amyl-l-methyl-4- ethyldecylamine 'cyclohexanephosphonatc,' 1 methyl 4'-, I ethyldodecylamine cctylsulfate and 2-isopropyldecylamine phenylmaleate.

The branched chain amine and amine salts of the present invention effect the desired improvement in the base oil when added thereto in minor percentages, and good results have been obtained using from about 1 to by weight of the amine or amine salt additive. In some cases amounts considerably smaller thanl%, as from about 0.1 to 0.3%, impart appreciable detergent properties to the oil, and amounts as small as this can frequently be employed, particularly when the oil is also fortified with other additives. Conversely, amounts of the present additive larger than 20% can be employed on occasion, as for example when the oil is to be used in engines known to generate exceptionally large quantities of acids on combustion of their fuels, and again in lubricants which are compounded with exceptionally large quantities of the additive and are primarily intended to be combined with more dilute, or uncompounded lubricant oils.

The compounding agents of this invention are not limited in their applicability to any particular base oil stock, but can be combined with any oil having the dcsircd lubricating properties. Thus, depending on the conditions and service which the compounded oil is to encounter, the base oil stock can be a Pennsylvania or other paraffinic base oil, a refined naphthenic base oil, or a synthetic hydrocarbon or non-hydrocarbon oil of lubricating viscosity. As synthetic oils there can be mentioned alkylated waxes and other hydrocarbons of high molecular weight, hydrogenated polymers of olefin hydrocarbons and the condensaton products of chlorin ated alkyl hydrocarbons with aryl compounds. Other suitable synthetic oils are those which are obtained by the polymerization of lower molecular weight alkylenc oxides such as propylene and/or ethylcuc oxidc. Still other synthetic oils are obtained by ctherification and/or other additives suchas other mineral oil detergents (e. g.,' polyvalent metal phenatcs, sulfon'ates, thiophosphates,

ing agents, blooming agents, compounds for enhancing the viscosity index of the oil, and thickening agents. There alsocan'be employed metal soaps .in either greaseforming proportions or in amounts insufficient to :form grease, as in the case of mineral castor machine oils or I othcr compounded liquid lubricants. In many cases, it

is desirable to avoid the us eof metal-containing additives, I in which case'o'n'ly secondary ingredients of non-metallic,

character should be added to the oil.

' The following examples illustrate the in various of its embodiments;

' Example I I In this operation the corrosivity of a lubricant composition containing branched chain amine or amine salt additives was measured and compared with that of the unco'rnpou'nded base oil as well as with that of thesame base oil'compoundcd witha non-branched chain amine" or amine salt additive.

In these tests the base oil, employed was a highly refined product of SAEBO grade having a V. I. of.85 andderivedfrorn California waxy crude. These tests were conducted byimm'ersing highly polished sections of a copper-lead'bcaring insert measuring about 2 /2"x "xl of known weightin the test oil. The oil surrounding the insert was then heated to a temperature of 300 'F. and maintained at this temperature, with stirring, for 20 hours. At the end of this time the strip was removed from the oil and cleaned, first with chloroform and then with petroleum ether. The cleaned strip was then weighed and the difference in weight between the original strip and the solventwashed strip was noted and recorded as weight loss due to corrosion by the oil composition. Other tests were conducted in the same manner, but with the specimen being left in the heated test oil, with stirring, for a period of 40 hours. In each case the additive was present in the amount of 5%, except in the case of the base oil, which contained no additive. The weight loss experienced by the test specimens in the various oil compositions is given in Table I below.

TABLE I [Cu-Pb strip corrosion data] Wei ht Loss in s. Additive g g 20 Hrs. 40 Hrs.

None.. 45. 6 65. 4 Iso ctadecylamine 41. 6 64. 3 N-butyl-isooctadecylamine.- 15. 4 e2. 4 N-octadecyl-isooctadecylamin 57. 5 75. 5 N-dodecylamine 289. 4 44!. 8 N-o ctadecylaminc.-. 278.. 7 451. 4 di-n-octadecylamine 146. 2 171. 1 Isooctadecylamiue alkauephosphonats 53. 9 95. 4 n-octadeeylamtne alkancphosphonate 321.1 414. 9 Isooctadecylamine cetylmaleate 90. 8 122.3 n-dodecylamine cctylmaleate 169. 5. 261.9 Isooctadec lamina 01eate- 105.6 133. 6

n-oetadecy amine oleate. 249. 4 388.

l The nlkanephosphonate is derived from petroleum white 01!.

present invention 1 From the above data, it will be seen that the lubricant compositions compounded with branched chain amines and aminesalts afford a degree of protection from corrosion which is far superior to that of the other compounds tested, and oils which are relatively non-corrosive as shownby this test are admirably suited for use, not only in diesel and other internal combustion engines, but also as electrical insulating oils, cable oils, turbine oils and the like, as well.

Example 11 In this operation the detergency qualities imparted to a base oil by the addition of 5% isooctadecylamine are measured and compared with those of the uncompounded base oil (a highly refined base oil, SAE 30, 85 V. 1., derived from California waxy crude), as well as with those of a commercial heavy duty oil (of the same base stock) now commonly employed in diesel engines. In this test a C. R. C., L-l type Caterpillar single cylinder test engine was maintained in continuous operation for a period of 120 hours, the exhaust temperature being 800 F. The quality of the oil was evaluated at the end of the run by disassembling the engine and inspecting the four ring grooves in the piston for deposit and the intervening lands for discoloration. The amount of deposit found to be present in each groove is expressed in Table II below in terms of G. D. (Groove Deposit) numbers, the scale employed being 0 to 100, with 0 indicating the absence of any deposit and with 100 indicating a complete filling of the groove. The extent of discoloration on the lands was measured and is expressed in Table II below in terms of Land P. D. (Piston Discoloration) numbers. In obtaining the P. D. numbers, a value of 0 was assigned to a land which was completely clean, whereas one which was completely black was given a value of 800, with intermediate numbers being assigned to areas falling between these two extremes. The fuel employed contained between 0.4 and 1% sulfur.

TABLE II [L1 type Caterpillar engine data (120 hrs.800 F. exhaust temp.).]

G. D. Nos. Land P. D. NOS.

Lubricant Ring Ring Ring Ring Land Land Land 1 2 3 4 1 2 3 Duty 0 We claim:

1. A lubricant composition comprising a major portion of an oil of lubricating viscosity and a minor percentage, sufiicient to impart detergent qualities to the oil, of at least one amino compound selected from the group consisting of (1) alkyl amines having attached to the amino nitrogen atom at least one branched chain alkyl radical having at least 10 carbon atoms, said alkyl radical being attached to the amino nitrogen atom through a tertiary carbon atom and (2) salts of said amines and an organic acid selected from the group consisting of oleic acid, cetyl maleic acid and alkane phos phonic acid derived from petroleum white oil, said composition being characterized by-Jow corrosivity to bearing and other metal surfaces.

2. The composition of claim 1, wherein the amino compound is present in an amount of from about 1 to 20% by weight.

3. A lubricant composition comprising a major portion of an oil of lubricating viscosity and a minor percentage, suflicient to impart detergent qualities to the oil, of an alkyl amine having attached to the amino ni trogen atom at least one branched chain alkyl radical having at least 10 carbon atoms, said alkyl radical being attached to the amino nitrogen atom through a tertiary carbon atom said composition being characterized by low corrosivity to bearing and other metal surfaces.

4. A lubricant composition comprising a major portion of an oil of lubricating viscosity and a minor percentage, suificient to impart detergent qualities to the oil, of a salt of an alkyl amine and an organic acid selected from the group consisting of oleic acid, cetyl maleic acid and alkane phosphonic acid derived from petroleum white oil having attached to the amino nitrogen atom at least one branched chain alkyl radical having at least 10 carbon atoms, said alkyl radical being attached to the amino nitrogen atom through a tertiary carbon atom, said composition being characterized by low corrosivity to hearing and other metal surfaces.

5. A lubricant composition comprising a major portion of an oil of lubricating viscosity and a minor percentage, sufiicient to impart detergent qualities to the oil, of an alkyl amine wherein at least one alkyl radical containing at least 10 carbon atoms is attached to the amino nitrogen atom through a tertiary carbon atom, said composition being characterized by low corrosivity to hearing and other metal surfaces.

6. A lubricant composition comprising a major portion of an oil of lubricating viscosity and a minor percentage, sufiicient to impart detergent qualities to the oil, of a salt of an alkyl amine and an organic acid selected from the group consisting of oleic acid, cetyl maleic acid and alkane phosphonic acid derived from pctroleum white oil wherein at least one alkyl radical containing at least 10 carbon atoms is attached to the amino nitrogen atom through a tertiary carbon atom, said composition being characterized by low corrosivity to hearing and other metal surfaces.

7. The composition of claim 5, wherein the amine is. isooctadecy amine.

8. The composition of claim 5, wherein the amine is N-butyl-isooctadecy amine.

9. The composition of claim 5, wherein the amine is N-n-octadecyl-isooctadecyl amine.

References Cited in the file of this patent UNITED STATES PATENTS 1,888,023 Adams Nov. 15, 1932 2,234,096 Teter Mar. 4, 1941 2,413,852 Turner Jan. 7, 1947 2,476,271 Bartleson July 19, 1949 

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR PORTION OF AN OIL OF LUBRICATING VISCOSITY AND A MINOR PERCENTAGE, SUFFICIENT TO IMPART DETERGENT QUALITIES TO THE OIL, OF AT LEAST ONE AMINO COMPOUND SELECTED FROM THE GROUP CONSISTING OF (1) ALKYL AMINES HAVING ATTACHED TO THE AMINO NITROGEN ATOM AT LEAST ONE BRANCHED CHAIN ALKYL RADICAL HAVING AT LEAST 10 CARBON ATOMS, SAID ALKYL RADICAL BEING ATTACHED TO THE AMINO NITROGEN ATOM THROUGH A TERTIARY CARBON ATOM AND (2) SALTS OF SAID AMINES AND AN ORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF OLEIC ACID, CETYL MATELIC ACID AND ALKANE PHOSPHONIC ACID DERIVED FROM PETROLEUM WHITE OIL, SAID COMPOSITION BEING CHARACTERIZED BY LOW CORROSIVITY TO BEARING AND OTHER METAL SURFACES. 